Diseases of the eye are the leading cause of blindness in the world today. Many diseases affect different parts of the eye, and are diagnosed by imaging and inspecting images of different parts of the eye. These parts of the eye may include the retina, the posterior segment, the lens, the anterior segment, the cornea, the sclera, or external aspects of the eye such as the eyelid and orbital. Examples of diseases that affect the eye include conditions such as retinal detachment, retinopathy caused by diabetes, hypertension or other condition, glaucoma, cataract, abrasions and lacerations of the cornea or sclera.
Many of these conditions do not present significant symptoms, and diagnosis of eye conditions such as those listed above typically occurs at a physician's or optometrist's office during the course of a routine checkup. The eye is usually examined with an ophthalmoscope or other imaging equipment, and trained physicians or optometrists usually make a diagnosis without any context of how the subject's eye has changed over time. In some cases, computer aided diagnosis (CAD) software may be used to analyze images and provide assistance to the physician, but usually these algorithms do not utilize prior history or other images of the subject's eye.
Individuals, including those at risk for such conditions, usually receive such routine checkups from their physician or optometrist every 6 months to 2 years. As a result, it may be possible for diseases of the eye to develop and go undiagnosed for years, at which point, they may be more expensive to treat or may have reached an advanced state resulting in a worse prognosis.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a system to capture images an ocular scene repeatedly and conveniently in a home environment, using a calibration image taken by a trained physician. There is also a need to track changes in the images of the ocular scene relative to calibration images of the ocular scene, taken by a trained physician, and in particular to track changes in the images of the ocular scene at particular landmarks corresponding to physician specified landmarks in the associated calibration image.